Penicillium sp. spores, coloured scanning electron micrograph (SEM). The round structures seen here are conidia, the asexual reproductive spores of the fungus. Each chain of conidia grows on a specialised hypha (stalk) known as a conidiophore. This is a common mould that is often found growing on bread. Magnification: x1,500 when printed at 15cm wide.